ISLAMABAD: President Asif Ali Zardari congratulated his US counterpart Barack Obama on his re-election Wednesday, saying he was confident their countries' relations would "continue to prosper".   The fractious friends lurched from crisis to crisis in 2011, first over a CIA contractor who shot dead two people in Lahore, then over the US raid that found and killed Osama bin Laden, and finally over botched air strikes that killed 24 Pakistani border guards.   "President Asif Ali Zardari has warmly felicitated President Barack Obama on his re-election as the President of the United States of America," a statement issued by Pakistan's Foreign Ministry said.   "The President expressed the hope that the relationship between Pakistan and the US would continue to prosper during President Obama's new term in office."   Islamabad and Washington have been seeking to improve their relationship in recent months, with Pakistan reopening the NATO supply route to Afghanistan which it closed for six months ...